1. Field of the Invention
The present invention relates generally to optical alignment devices, and more particularly to an optical alignment device and method for use in photographic testing equipment.
2. Description of the Prior Art
In the field of projectile or missile flight analysis, a more accurate analysis has been obtained by using flash x-ray tubes and x-ray film. The resulting flash radiograph is used to measure the flight characteristics of the missile, including velocity. In order for accurate measurements to be made, it is critical that each individual flash x-ray tube be aligned perpendicular to an identifiable point on the surface of the x-ray film. For each measuring position, a pair of flash tubes are provided projecting onto separate film surfaces, ninety degrees apart. The previous method for aligning each flash x-ray tube involved setting up a transit or a theodolite and properly aligning it perpendicular to the surface of one of the films. Then as one individual looks through the transit, a second individual aligns the flash x-ray tube. Once a pair has been aligned, the transit is realigned to assure a perpendicular relationship to the plane of the film and the next pair of x-ray tubes are aligned. This process is repeated and may require as many as six movements in alignment in order to assure alignment of all of the tubes.
In addition to the number of movements, alignment, and personnel involved in properly aligning the flash x-ray tubes and the x-ray film, the flash radiography test equipment are generally located in an armored enclosure with a minimum amount of room for transit and personnel. This space limitation increases the time involved in setting up the transit and moving it for each alignment. Also, the transit has to be removed from the armored enclosure before each round is fired to prevent possible damage to as delicate an instrument as the transit. It should be noted that alignment with the transit involves a team of trained personnel familiar with the operation and use of the transit.
Thus there is a long-felt need for a simple portable optical alignment device for use in flash radiography by untrained personnel.